Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Fri, 30 Aug 2019 10:01:31 +0200
From:   Jiri Pirko <jiri@resnulli.us>
To:     David Miller <davem@davemloft.net>
Cc:     idosch@idosch.org, andrew@lunn.ch, horatiu.vultur@microchip.com,
        alexandre.belloni@bootlin.com, UNGLinuxDriver@microchip.com,
        allan.nielsen@microchip.com, ivecera@redhat.com,
        f.fainelli@gmail.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 1/2] net: core: Notify on changes to dev->promiscuity.
Message-ID: <20190830080131.GQ2312@nanopsycho>
References: <20190830063624.GN2312@nanopsycho>
 <20190830.001223.669650763835949848.davem@davemloft.net>
 <20190830072133.GP2312@nanopsycho>
 <20190830.003225.292019185488425085.davem@davemloft.net>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20190830.003225.292019185488425085.davem@davemloft.net>
User-Agent: Mutt/1.11.4 (2019-03-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Fri, Aug 30, 2019 at 09:32:25AM CEST, davem@davemloft.net wrote:
>From: Jiri Pirko <jiri@resnulli.us>
>Date: Fri, 30 Aug 2019 09:21:33 +0200
>
>> Fri, Aug 30, 2019 at 09:12:23AM CEST, davem@davemloft.net wrote:
>>>From: Jiri Pirko <jiri@resnulli.us>
>>>Date: Fri, 30 Aug 2019 08:36:24 +0200
>>>
>>>> The promiscuity is a way to setup the rx filter. So promics == rx filter
>>>> off. For normal nics, where there is no hw fwd datapath,
>>>> this coincidentally means all received packets go to cpu.
>>>
>>>You cannot convince me that the HW datapath isn't a "rx filter" too, sorry.
>> 
>> If you look at it that way, then we have 2: rx_filter and hw_rx_filter.
>> The point is, those 2 are not one item, that is the point I'm trying to
>> make :/
>
>And you can turn both of them off when I ask for promiscuous mode, that's
>a detail of the device not a semantic issue.

Well, bridge asks for promiscuous mode during enslave -> hw_rx_filter off
When you, want to see all traffic in tcpdump -> rx_filter off

So basically there are 2 flavours of promiscuous mode we have to somehow
distinguish between, so the driver knows what to do.

Nothe that the hw_rx_filter off is not something special to bridge.
There is a usecase for this when no bridge is there, only TC filters for
example.